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From: "Abhishek Kumar via GitGitGadget" <gitgitgadget@gmail.com>
To: git@vger.kernel.org
Cc: "Derrick Stolee" <stolee@gmail.com>,
	"Jakub Narębski" <jnareb@gmail.com>,
	"Abhishek Kumar" <abhishekkumar8222@gmail.com>,
	"SZEDER Gábor" <szeder.dev@gmail.com>,
	"Taylor Blau" <me@ttaylorr.com>,
	"Abhishek Kumar" <abhishekkumar8222@gmail.com>,
	"Abhishek Kumar" <abhishekkumar8222@gmail.com>
Subject: [PATCH v7 01/11] commit-graph: fix regression when computing Bloom filters
Date: Mon, 01 Feb 2021 06:58:35 +0000	[thread overview]
Message-ID: <9ac331b63ee609f5380649d3b395f420e57e56f8.1612162726.git.gitgitgadget@gmail.com> (raw)
In-Reply-To: <pull.676.v7.git.1612162726.gitgitgadget@gmail.com>

From: Abhishek Kumar <abhishekkumar8222@gmail.com>

Before computing Bloom filters, the commit-graph machinery uses
commit_gen_cmp to sort commits by generation order for improved diff
performance. 3d11275505 (commit-graph: examine commits by generation
number, 2020-03-30) claims that this sort can reduce the time spent to
compute Bloom filters by nearly half.

But since c49c82aa4c (commit: move members graph_pos, generation to a
slab, 2020-06-17), this optimization is broken, since asking for a
'commit_graph_generation()' directly returns GENERATION_NUMBER_INFINITY
while writing.

Not all hope is lost, though: 'commit_gen_cmp()' falls back to
comparing commits by their date when they have equal generation number,
and so since c49c82aa4c is purely a date comparison function. This
heuristic is good enough that we don't seem to loose appreciable
performance while computing Bloom filters.

Applying this patch (compared with v2.30.0) speeds up computing Bloom
filters by factors ranging from 0.40% to 5.19% on various repositories [1].

So, avoid the useless 'commit_graph_generation()' while writing by
instead accessing the slab directly. This returns the newly-computed
generation numbers, and allows us to avoid the heuristic by directly
comparing generation numbers.

[1]: https://lore.kernel.org/git/20210105094535.GN8396@szeder.dev/

Signed-off-by: Abhishek Kumar <abhishekkumar8222@gmail.com>
---
 commit-graph.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/commit-graph.c b/commit-graph.c
index f3486ec18f1..78de312ccec 100644
--- a/commit-graph.c
+++ b/commit-graph.c
@@ -139,13 +139,17 @@ static struct commit_graph_data *commit_graph_data_at(const struct commit *c)
 	return data;
 }
 
+/* 
+ * Should be used only while writing commit-graph as it compares
+ * generation value of commits by directly accessing commit-slab.
+ */
 static int commit_gen_cmp(const void *va, const void *vb)
 {
 	const struct commit *a = *(const struct commit **)va;
 	const struct commit *b = *(const struct commit **)vb;
 
-	uint32_t generation_a = commit_graph_generation(a);
-	uint32_t generation_b = commit_graph_generation(b);
+	uint32_t generation_a = commit_graph_data_at(a)->generation;
+	uint32_t generation_b = commit_graph_data_at(b)->generation;
 	/* lower generation commits first */
 	if (generation_a < generation_b)
 		return -1;
-- 
gitgitgadget


  reply	other threads:[~2021-02-01  7:00 UTC|newest]

Thread overview: 211+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-28  9:13 [PATCH 0/6] [GSoC] Implement Corrected Commit Date Abhishek Kumar via GitGitGadget
2020-07-28  9:13 ` [PATCH 1/6] commit-graph: fix regression when computing bloom filter Abhishek Kumar via GitGitGadget
2020-07-28 15:28   ` Taylor Blau
2020-07-30  5:24     ` Abhishek Kumar
2020-08-04  0:46   ` Jakub Narębski
2020-08-04  0:56     ` Taylor Blau
2020-08-04 10:10       ` Jakub Narębski
2020-08-04  7:55     ` Jakub Narębski
2020-07-28  9:13 ` [PATCH 2/6] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2020-07-28 13:00   ` Derrick Stolee
2020-07-28 15:30     ` Taylor Blau
2020-08-05 23:16   ` Jakub Narębski
2020-07-28  9:13 ` [PATCH 3/6] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2020-07-28 13:14   ` Derrick Stolee
2020-07-28 15:19     ` René Scharfe
2020-07-28 15:58       ` Derrick Stolee
2020-07-28 16:01     ` Taylor Blau
2020-07-30  6:07     ` Abhishek Kumar
2020-07-28  9:13 ` [PATCH 4/6] commit-graph: consolidate compare_commits_by_gen Abhishek Kumar via GitGitGadget
2020-07-28 16:03   ` Taylor Blau
2020-07-28  9:13 ` [PATCH 5/6] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2020-07-28 16:12   ` Taylor Blau
2020-07-30  6:52     ` Abhishek Kumar
2020-07-28  9:13 ` [PATCH 6/6] commit-graph: implement corrected commit date offset Abhishek Kumar via GitGitGadget
2020-07-28 15:55   ` Derrick Stolee
2020-07-28 16:23     ` Taylor Blau
2020-07-30  7:27     ` Abhishek Kumar
2020-07-28 14:54 ` [PATCH 0/6] [GSoC] Implement Corrected Commit Date Taylor Blau
2020-07-30  7:47   ` Abhishek Kumar
2020-07-28 16:35 ` Derrick Stolee
2020-08-09  2:53 ` [PATCH v2 00/10] " Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 01/10] commit-graph: fix regression when computing bloom filter Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 02/10] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 03/10] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 04/10] commit-graph: consolidate compare_commits_by_gen Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 05/10] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2020-08-10 16:28     ` Derrick Stolee
2020-08-11 11:03       ` Abhishek Kumar
2020-08-11 12:27         ` Derrick Stolee
2020-08-11 18:58           ` Taylor Blau
2020-08-09  2:53   ` [PATCH v2 06/10] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 07/10] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2020-08-10 14:23     ` Derrick Stolee
2020-08-14  4:59       ` Abhishek Kumar
2020-08-14 12:24         ` Derrick Stolee
2020-08-09  2:53   ` [PATCH v2 08/10] commit-graph: handle mixed generation commit chains Abhishek Kumar via GitGitGadget
2020-08-10 16:42     ` Derrick Stolee
2020-08-11 11:36       ` Abhishek Kumar
2020-08-11 12:43         ` Derrick Stolee
2020-08-09  2:53   ` [PATCH v2 09/10] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2020-08-09  2:53   ` [PATCH v2 10/10] doc: add corrected commit date info Abhishek Kumar via GitGitGadget
2020-08-10 16:47   ` [PATCH v2 00/10] [GSoC] Implement Corrected Commit Date Derrick Stolee
2020-08-15 16:39   ` [PATCH v3 00/11] " Abhishek Kumar via GitGitGadget
2020-08-15 16:39     ` [PATCH v3 01/11] commit-graph: fix regression when computing bloom filter Abhishek Kumar via GitGitGadget
2020-08-17 22:30       ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 02/11] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2020-08-18 14:18       ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 03/11] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2020-08-19 17:54       ` Jakub Narębski
2020-08-21  4:11         ` Abhishek Kumar
2020-08-25 11:11           ` Jakub Narębski
2020-09-01 11:35             ` Abhishek Kumar
2020-08-15 16:39     ` [PATCH v3 04/11] commit-graph: consolidate compare_commits_by_gen Abhishek Kumar via GitGitGadget
2020-08-17 13:22       ` Derrick Stolee
2020-08-21 11:05       ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 05/11] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2020-08-21 13:14       ` Jakub Narębski
2020-08-25  5:04         ` Abhishek Kumar
2020-08-25 12:18           ` Jakub Narębski
2020-09-01 12:06             ` Abhishek Kumar
2020-09-03 13:42               ` Jakub Narębski
2020-09-05 17:21                 ` Abhishek Kumar
2020-09-13 15:39                   ` Jakub Narębski
2020-09-28 21:48                     ` Jakub Narębski
2020-10-05  5:25                       ` Abhishek Kumar
2020-08-15 16:39     ` [PATCH v3 06/11] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget
2020-08-21 18:43       ` Jakub Narębski
2020-08-25  6:14         ` Abhishek Kumar
2020-08-25  7:33           ` Jakub Narębski
2020-08-25  7:56             ` Jakub Narębski
2020-09-01 10:26               ` Abhishek Kumar
2020-09-03  9:25                 ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 07/11] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2020-08-22  0:05       ` Jakub Narębski
2020-08-25  6:49         ` Abhishek Kumar
2020-08-25 10:07           ` Jakub Narębski
2020-09-01 11:01             ` Abhishek Kumar
2020-08-15 16:39     ` [PATCH v3 08/11] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2020-08-22 13:09       ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 09/11] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget
2020-08-22 17:14       ` Jakub Narębski
2020-08-26  7:15         ` Abhishek Kumar
2020-08-26 10:38           ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 10/11] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2020-08-22 19:09       ` Jakub Narębski
2020-09-01 10:08         ` Abhishek Kumar
2020-09-03 19:11           ` Jakub Narębski
2020-08-15 16:39     ` [PATCH v3 11/11] doc: add corrected commit date info Abhishek Kumar via GitGitGadget
2020-08-22 22:20       ` Jakub Narębski
2020-08-27  6:39         ` Abhishek Kumar
2020-08-27 12:43           ` Jakub Narębski
2020-08-27 13:15           ` Derrick Stolee
2020-09-01 13:01             ` Abhishek Kumar
2020-08-17  0:13     ` [PATCH v3 00/11] [GSoC] Implement Corrected Commit Date Jakub Narębski
     [not found]       ` <CANQwDwdKp7oKy9BeKdvKhwPUiq0R5MS8TCw-eWGCYCoMGv=G-g@mail.gmail.com>
2020-08-17  1:32         ` Fwd: " Taylor Blau
2020-08-17  7:56           ` Jakub Narębski
2020-08-18  6:12       ` Abhishek Kumar
2020-08-23 15:27       ` Jakub Narębski
2020-08-24  2:49         ` Abhishek Kumar
2020-10-07 14:09     ` [PATCH v4 00/10] " Abhishek Kumar via GitGitGadget
2020-10-07 14:09       ` [PATCH v4 01/10] commit-graph: fix regression when computing Bloom filters Abhishek Kumar via GitGitGadget
2020-10-24 23:16         ` Jakub Narębski
2020-10-25 20:58           ` Taylor Blau
2020-11-03  5:36             ` Abhishek Kumar
2020-10-07 14:09       ` [PATCH v4 02/10] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2020-10-24 23:41         ` Jakub Narębski
2020-10-07 14:09       ` [PATCH v4 03/10] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2020-10-25 10:52         ` Jakub Narębski
2020-10-27  6:33           ` Abhishek Kumar
2020-10-07 14:09       ` [PATCH v4 04/10] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2020-10-25 13:48         ` Jakub Narębski
2020-11-03  6:40           ` Abhishek Kumar
2020-10-07 14:09       ` [PATCH v4 05/10] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget
2020-10-25 22:17         ` Jakub Narębski
2020-10-07 14:09       ` [PATCH v4 06/10] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2020-10-27 18:53         ` Jakub Narębski
2020-11-03 11:44           ` Abhishek Kumar
2020-11-04 16:45             ` Jakub Narębski
2020-11-05 14:05               ` Philip Oakley
2020-11-05 18:22                 ` Junio C Hamano
2020-11-06 18:26                   ` Extending and updating gitglossary (was: Re: [PATCH v4 06/10] commit-graph: implement corrected commit date) Jakub Narębski
2020-11-06 19:33                     ` Extending and updating gitglossary Junio C Hamano
2020-11-08 17:23                     ` Extending and updating gitglossary (was: Re: [PATCH v4 06/10] commit-graph: implement corrected commit date) Philip Oakley
2020-11-10  1:35                       ` Extending and updating gitglossary Jakub Narębski
2020-11-10 14:04                         ` Philip Oakley
2020-11-10 23:52                           ` Jakub Narębski
2020-10-07 14:09       ` [PATCH v4 07/10] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2020-10-30 12:45         ` Jakub Narębski
2020-11-06 11:25           ` Abhishek Kumar
2020-11-06 17:56             ` Jakub Narębski
2020-10-07 14:09       ` [PATCH v4 08/10] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget
2020-11-01  0:55         ` Jakub Narębski
2020-11-12 10:01           ` Abhishek Kumar
2020-11-13  9:59             ` Jakub Narębski
2020-10-07 14:09       ` [PATCH v4 09/10] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2020-11-03 17:59         ` Jakub Narębski
2020-11-03 18:19           ` Junio C Hamano
2020-11-20 10:33           ` Abhishek Kumar
2020-10-07 14:09       ` [PATCH v4 10/10] doc: add corrected commit date info Abhishek Kumar via GitGitGadget
2020-11-04  1:37         ` Jakub Narębski
2020-11-21  6:30           ` Abhishek Kumar
2020-11-04 23:37       ` [PATCH v4 00/10] [GSoC] Implement Corrected Commit Date Jakub Narębski
2020-11-22  5:31         ` Abhishek Kumar
2020-12-28 11:15       ` [PATCH v5 00/11] " Abhishek Kumar via GitGitGadget
2020-12-28 11:15         ` [PATCH v5 01/11] commit-graph: fix regression when computing Bloom filters Abhishek Kumar via GitGitGadget
2020-12-30  1:35           ` Derrick Stolee
2021-01-08  5:45             ` Abhishek Kumar
2021-01-05  9:45           ` SZEDER Gábor
2021-01-05  9:47             ` SZEDER Gábor
2021-01-08  5:51             ` Abhishek Kumar
2020-12-28 11:15         ` [PATCH v5 02/11] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 03/11] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 04/11] t6600-test-reach: generalize *_three_modes Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 05/11] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 06/11] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 07/11] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2020-12-30  1:53           ` Derrick Stolee
2021-01-10 12:21             ` Abhishek Kumar
2020-12-28 11:16         ` [PATCH v5 08/11] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 09/11] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget
2020-12-30  3:23           ` Derrick Stolee
2021-01-10 13:13             ` Abhishek Kumar
2021-01-11 12:43               ` Derrick Stolee
2020-12-28 11:16         ` [PATCH v5 10/11] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2020-12-28 11:16         ` [PATCH v5 11/11] doc: add corrected commit date info Abhishek Kumar via GitGitGadget
2020-12-30  4:35         ` [PATCH v5 00/11] [GSoC] Implement Corrected Commit Date Derrick Stolee
2021-01-10 14:06           ` Abhishek Kumar
2021-01-16 18:11         ` [PATCH v6 " Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 01/11] commit-graph: fix regression when computing Bloom filters Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 02/11] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 03/11] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 04/11] t6600-test-reach: generalize *_three_modes Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 05/11] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 06/11] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 07/11] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 08/11] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 09/11] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 10/11] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2021-01-16 18:11           ` [PATCH v6 11/11] doc: add corrected commit date info Abhishek Kumar via GitGitGadget
2021-01-27  0:04             ` SZEDER Gábor
2021-01-30  5:29               ` Abhishek Kumar
2021-01-31  1:45                 ` Taylor Blau
2021-01-18 21:04           ` [PATCH v6 00/11] [GSoC] Implement Corrected Commit Date Derrick Stolee
2021-01-18 22:00             ` Taylor Blau
2021-01-23 12:11               ` Abhishek Kumar
2021-01-19  0:02             ` Junio C Hamano
2021-01-23 12:07             ` Abhishek Kumar
2021-02-01  6:58           ` [PATCH v7 " Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` Abhishek Kumar via GitGitGadget [this message]
2021-02-01  6:58             ` [PATCH v7 02/11] revision: parse parent in indegree_walk_step() Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 03/11] commit-graph: consolidate fill_commit_graph_info Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 04/11] t6600-test-reach: generalize *_three_modes Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 05/11] commit-graph: add a slab to store topological levels Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 06/11] commit-graph: return 64-bit generation number Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 07/11] commit-graph: document generation number v2 Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 08/11] commit-graph: implement corrected commit date Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 09/11] commit-graph: implement generation data chunk Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 10/11] commit-graph: use generation v2 only if entire chain does Abhishek Kumar via GitGitGadget
2021-02-01  6:58             ` [PATCH v7 11/11] commit-reach: use corrected commit dates in paint_down_to_common() Abhishek Kumar via GitGitGadget
2021-02-01 13:14             ` [PATCH v7 00/11] [GSoC] Implement Corrected Commit Date Derrick Stolee
2021-02-01 18:26               ` Junio C Hamano

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